Method of recovering carbon bisulphide



' ee'o'r preferred form of condenser.

Patent ed July 22, 1930 UNITED ST TES PATENT j orrlcs 1 CHARLES J. STROBACKER AND JAMES I. JONES, OF MIDLAND, MICHIGAN, ABS IGNORS TO THE DOW CHEMICAL COMPANY, 02 MIDLAND, MICHIGAN, A. CORPORATION 01' MICE rem I un'rnon or nncovname cannon nrsunrnma Io Drawing. Original application flied January 25, 1986, Serial Io. 88,711'. Divided and this application flied December 7, 1928. Serial No. 153,208.

The method largely employed for the manufacture of carbon "bisulphide consists in passing the vapor of sulphur over red hot charcoal or coke. Such sulphur vapor combines directly with the red hot carbon to form the carbon bisulphide together with various impurities, the principal one of which is hydrogen sulphide. This hydrogen -sul-" phide passin through the condensers,'which c are employe to condense the carbon bisulphide carries with it considerable carbon bisulphide, .the amount depending upon the temperature. Cooling alone is not adequate to effect aseparation, and there is accordingly a corresponding loss of carbon bisulhide so carried away. It is among the obects of thepresent invention to recover this 'carbon bisulphide by bringing the hydrogen sulphide and the carbon bisulphide vapor into contact with a suitable reagent whereby the hydrogen sulphide is absorbed, but the carbon bisulphide is unacted upon, and can then be condensed.

To the accomplishment of the foregoing 85 and related ends, the invention, then, consists of the steps hereinafter fully described, and particularly pointed out in the claims, the followingdescription setting forth but one of the various ways in which the prin-' 80 m le of the invention may be emplo ed.

n proceeding in accordance wit our invention the mixture of hydrogen sulphide and carbon bisulphide is brought into contact with sodium sulphide, preferably in aqueous solution. The strength of such solution may vary, but preferably may be about ;20., B6; The contacting of the hydrogen sulphide with the sodium sulphide, where the latter is employed in a ueous'solution, may 0) be carried out in a scrub r tower or the like, .or. preferably by bubbling the gas through thesolution inatank. Y

The h drogen sul hide reacts with the soon phide, as in icated by the equation- -Na,S +I-I=S=2NaHS I ,1. Innerthe hydrogen sulphide has been thus the. residual carbon bisulphide vapormaybe readily condensedin allay usual some .tion of the gas.

the one-e gards the et-ails disclosed, provided the step. 95

' or steps stated by any of the following claims.

step or steps cases, however, it is desirable to maintain the solution sufliciently cool so thatthe carbon bisulphide no longer remains volatilized, but condenses at the same time that the hydro en I sulphide is absorbed. The carbon bisulphlde in such event may then be separated b distillation, or if preferred, it can be rawn oflz as a layer, such decantation being readily feasible.

It-will be. understood of course that the present improved method of recovering carbon bisulphide is not necessarily limited to the case where this compound is made by the particular method before mentioned as the one generally employed for the production of such compound, but this method is applicable generally where gaseous products from the manufacture of carbon bisulphate includmg hydrogen sulphide are present and a separation is desired. Instead on passing the exit gases, from the condenser, into a water solution of sodium sulphide, they may be passed through a body of water, and the-sodium sulphide may be subsequently added. The water, if sufiicient in amount, will absorb the'h'ydrogen sulphide but has substantially no such effect on carbon bisulphide, and on the addition then of the sodium sulphide to thewater will allow fixaso The acid sodium sulphide resulting from the absorption may then be further treated with caustic soda, as in accordance with the reactionnans+mon=uas+mo The normal sulphide so resulting may then again be used for further absorpt1on.

The method herein described and claimed is a division of our co ending application, Serial No. 83,711, filed anuary 25, 1926.

Other modes of a plying the rinciple of our invention may em loyed lained, change .ing made as reor. the equivalent of such stated be employed.

' We therefore particularly distinctly claim as our invention instead of point out and w 1. A process of making carbon bisulphide and an alkali metal hydrosul hide which comprises passing the vapor 0 sulphur in contact with carbon at a red heat condensing the major portion of carbon bisu hide from the reaction products, subjecting t e residual non-condensible gaseous mixture of carbon I bisulphide and hydrogen sulphide to the action of an aqueous alkali metal sulphide solution to absorb such hydrogen sul hide, and condensing such residual carbon isulphide.

"2. A process of making carbon bisulphide and sodium hydrosulphide which comprises passing the vapor of sulphur in contact ivith carbon at a red heat, condensing the major portion of carbon bisulphide from the reaction products, subjecting the residual noncondensible gaseous mixture of carbon bisulphide and hydrogen sulphide to the action of anaqueous sodium sulphide solution to absorb such h d rogen sulphide, and condensin such resi ual carbon isulphide.

CHARLES J. STROSACKER, JAMES I. JONES.

gned by us this 2nd day of December, 

